A lesson to be learned!Substrate: noun
a solid substance or medium to which another substance is applied and to which that second substance adheres.
Case in point my latest watercolor technique. This blog wasn't going to be about paper and the significant role it plays in your card projects .... but I figured why waste a good learning opportunity.
(of a material, substance, or byproduct) eliminated or discarded as no longer useful or required after the completion of a process.